The present invention relates generally to an occult blood test product, of the type to be physically placed into a toilet bowl containing a fecal specimen, for detecting the presence of fecal occult blood in an aqueous solution. More particularly, the present invention relates to an improved, reliable fecal occult blood test product which may be utilized with a minimum of human intervention. The principles of the present invention may be employed in the testing for occult blood, ferritin and myoglobin in various biological fluids.
In general terms, the testing of a fecal specimen for occult blood is based on the well-known principle that blood (more particularly hemoglobin) will function as a catalyst and cause oxygen to be liberated from an oxygen donor, with the liberated oxygen thus causing a color change in a chromogenic substance. As such, the test for fecal occult blood is not only well-known, but numerous oxygen donors, numerous chromogens and numerous donor-chromogen pairs have been suggested in the prior literature. In considering the chromogens and oxygen donors which may be used, it should be appreciated that the fecal occult blood test is frequently referred to as a test for the presence of a substance having a peroxidase-like activity.
In addition, there are several principle styles of fecal occult blood test products which have been marketed or described in the literatures. These include slides, tape, wipe and throw-in-the-bowl products. Slide products require the patient to retrieve part of the stool specimen and, using a spatula or equivalent device, place part of the specimen on a paper which paper is thereafter submitted to a laboratory where a developing solution is applied to the slide. Tape products are typically utilized by a physician after a rectal examination in which instance the physician smears a stool sample on a thin, narrow tape and then a developing solution is applied to the tape. In both of these types of products, the chromogen is guaiac, and the oxygen donor or developing solution is hydrogen peroxide.
A third type of product is often referred to as the wipe type of product where a form of toilet paper is impregnated with a suitable chemical, typically the chromogen, and after a bowel movement, the patient self-wipes the anal area, and thereafter may apply the developing solution to the paper. As may be appreciated, in each of these types of products there is a need for the patient (or physician) to physically handle or physically contact the fecal specimen. Thus, there is a natural reluctance to employ these types of products, notwithstanding that they are well-known as beneficial screening agents, to assist in the early detection of colorectal cancer and other gastrointestinal disorders.
In November 1979, U.S. Pat. No. 4,175,923 issued to William Friend. This patent described a fecal occult blood test product of the throw-in-the-bowl type where a guaiac impregnated sheet was sprayed with a developing solution (hydrogen peroxide) and then placed into a toilet bowl containing a fecal specimen. If blood was present, the blood catalyzed a chromogenic reaction, and a blue color was observed in the toilet bowl. The product described in the Friend patent also included a positive monitor which would turn blue if the chemicals were functioning properly. However, the product as described in the Friend patent still required patient intervention in that the patient was required to apply the developer to the test product.
Guadagno U.S. Pat. No. 4,541,987, issued Sep. 17, 1985, relates to a throw-in-the-bowl type of product which included both positive and negative test monitors. A product generally in accordance with the teachings of the Guadaono patent has been successfully marketed by Helena Laboratories Corporation, of Beaumont, Tex., under their trademark CS-T. Helena Laboratories Corporation is the Assignee of the Guadaono patent and Assignee of the instant application. The CS-T brand of fecal occult blood test product is commercially successful and medically reliable.
In addition to the CS-T brand of fecal occult blood test product, which is in the nature of a test pador sandwich of dry chemicals between layers of paper, a thin film type of product for throw-in-the-bowl fecal occult blood testing is known as described in the aforementioned Patel, et al. applications. However, the product of the type described in the Patel, et al. applications has not met with success in the market place even though it does not require patient intervention. The product of the Patel, et al. application does not include self-contained controls or monitors, and the product as marketed has heretofore utilized an external type of positive monitor which must be dropped into the toilet bowl.
Thus, there is a need for a less expensive, reliable, easy to use throw-in-the-bowl type of fecal occult blood test product which is easy to manufacture and provides consistent, reliable results, and which also includes built-in or self-contained positive and negative monitors. These self-contained monitors, of course, aid the patient because the monitors inform the patient if a positive or a negative result should be ignored as being induced by contaminants or being the result of loss of activity by the chromogen or oxygen donor. In this fashion, a patient will know to repeat a test rather than rely upon false test results.
Hence, the present invention responds to these needs by providing an improved formulation of film-type throw-in-the-bowl fecal occult blood type product.